haha markets.. u can get flowers but i doubt they actually will do the decorations for you? wholesalers are located all over singapore actually. you can try far east flora, which has alot alot of outlets.. so will be convenient for you wherever you live / having the ROM etc. there's also sing see soon, jimei... you can check them out. they charge differently tho, so would be good if you can go down and talk to them about your requirements, and see which of them quote the best price for you.